The device of Patent Reference 1 is for example known as an electromagnetic contact device.
In the electromagnetic contact device of this Patent Reference 1, an electromagnet, a movable contact point support arranged parallel to the electromagnet, a return spring which urges the movable contact point support toward an initial position, and a driving lever which transmits attraction movement and release movement of the electromagnet to the movable contact point support, are accommodated within a case.
The movable contact point support comprises a plurality of movable contact points, which moves against the return spring to perform open or close operations with fixed contact points arranged within the case in opposition to each of the movable contact points. The electromagnet comprises an excitation coil, a fixed core, and a movable core arranged in opposition to and capable of contacting and separating from the fixed core. The center portion in the length direction of the driving lever is axially supported via a pin within the case, one end is engaged with the movable contact point support, and another end is engaged with the movable core.
When the excitation coil of the electromagnet is in an excited state and the movable core of the electromagnet is attracted to the fixed core, the movement due to attraction of the movable core is transmitted to the driving lever, which rotates about the pin via a movable core conjoining portion. This rotation of the driving lever is transmitted to the movable contact point support via a movable contact point support conjoining portion, and the movable contact point support moves from the initial position to an operation position, so that each of the corresponding movable contact points and fixed contact points perform open and close operations. Further, when the excitation coil of the electromagnet enters a non-excited state, the urging force of the return spring causes the movable contact point support to move from the operation position to the original position.
In the device of Patent Reference 1, even when an excessive current flows and slight adhesion between movable contact points of the movable contact point support at the operation position and fixed contact points occurs so that the movable contact point support does not move to the initial position against the urging force of the return spring, the inertial force of the movable core which is pressed by the urging force of the return spring to perform release movement is transmitted via the driving lever as a force moving the movable contact point support to the initial position. This force acts as a force to pull apart the slightly adhering movable contact points and fixed contact points, and the movable contact point support can return to the initial position, so that even when excessive current flows, the electromagnetic contact device can operate normally.    Patent Reference 1: Japanese Patent Laid-open No. 556-128533 (FIG. 4)
In the electromagnetic contact device of Patent Reference 1, the driving lever is conjoined with the case via the pin, so that there is a problem that the time required for driving lever assembly is increased.
Further, in Patent Reference 1, the point of action of the driving lever transmitting movement of the movable core to the movable contact point support does not coincide with the line of action (line extending from the axial line) of the return spring applying a urging force to the movable contact point support, so there is a concern that a moment may be imparted to the moving movable contact point support, and there is a concern that sliding friction with the case may increase.
This invention focuses on the above unresolved problems of examples of the prior art, and has as an object of providing an electromagnetic contact device which enables removal, by normal operation, of the problem of light adhesion of contact point portions due to the flow of excessive current, and enables easy assembly of the driving lever linking the movable contact point support and the electromagnet, and in which moreover the movable contact point support can be operated without the occurrence of a moment.